Add docs link (#103)

* Added docs link to README

* Added docs to sidebar in-app

* Updated some tests

* Updated docs in media profile form

lib/pinchflat_web/controllers/media_profiles/media_profile_html/media_profile_form.html.heex

@@ -233,7 +233,7 @@
         field={f[:download_source_images]}
         type="toggle"
         label="Download Series Images"
-        help="Downloads poster and banner images for use with Jellyfin, Kodi, etc. Only works for full channels (not playlists)"
+        help="Downloads poster and banner images for use with Plex, Jellyfin, Kodi, etc. Only works for full channels (not playlists)"
         x-init="$watch('selectedPreset', p => p && (enabled = presets[p]))"
       />
     </section>